ObjectiveTo study wether muscle spindle afferents have the regulating effects on res piratory movement. MethodsExperiments were performed on 36 anesthetized, immobilized, bilater ally vagotomized and artificially ventilated rabbits. Using the phrenic nerve discharge as the respira tory index, this experiment have assessed the effects of muscle spindle afferents invoked by intraarte rial injection of succinylcholine(Sch) on respiration. Results①In 40(63.49% ) cases which had the facilitated effects, 23 (36.51%) cases had the effect of prolonged inspiratory phase and 17 (26.98 % ) cases had the effect of attenuated expiratory phase and augmented respiratory frequency. In addition,there were 11(17.46% ) cases which had the attenuated effects,and 4(6.35% ) cases which had the biphasic effects,and 8(12.7% ) cases which had no effects;②The effect of prolonged inspiratory phase mainly showed the prolongation of inspiratory duration(Ti), but the effect of at tenuated expiratory phase and augmented respiratory frequency mainly showed the decrease of expi ratory duration (Te) and the augmentation of respiratory frequency(RF) ;③The above facilitated ef fects of Sch were significantly attenuated by intramuscular application of bupivacaine to destroy the muscle spindles. ConclusionThese results suggest that muscle spindle afferents induced by intraar terial injection Sch have a significant facilitated effect on respiration.

Objective: To observe the effect of 2 Hz electroacupuncture (EA) on long term depression (LTD) of synaptic transmission in the spinal dorsal horn in rats with neuropathic pain, so as to explore the central mechanisms of the antinociceptive effects of 2 Hz electroacupuncture on neuropathic pain. Methods: The neuropathic pain models were produced by tight ligation of the L5/L6 spinal nerves in Sprague Dawley rats. The C fiber evoked field potentials in the spinal dorsal horn were recorded with extracellular recording techniques. The parameters of the electroacupuncture were as follows: frequency of 2 Hz, wavelength of 0.6 ms, intensity of 1,2,3 mA lasting 10 min for each intensity, stimulation time of 30 min. The positive stimulating electrode was placed in acupoint “sanyinjiao” and the negative electrode in “zusanli”. Results: (1) 2 Hz electroacupuncture significantly decreased the amplitudes of C fiber evoked field potentials in the spinal dorsal horn in rats with neuropathic pain to (49.4?0.6)% of the control, compared with that (100.1?1.2) % of the control before EA (unpaired t test, P

ObjectiveTo study the distribution, developmental patterns, and hormonal control of androgen re- ceptors(AR) in the developing and ethane dimethane sulfonate(EDS) treated male SD rat epididymis. MethodsThe ABC technique of immunohistochemistry and image analysis were used to assess optodensity means (OPTDM) of AR, providing a measure of relative nuclear AR concentration. ResultsThe specific AR immunostaining was observed in the nuclei of epididymal epithelium, peritubular smooth muscle cells and intertubular connective tissue cells. The rela- tive AR concentrations varied with the different segments of the epididymis in the adult rat(P<0. 05 or P<0.01). AR protein was highest in the caput (0. 763--0. 026),lowest in the corpus (0. 712±0. 025) and intermediate in the cauda (0. 736±0. 008). Levels of epididymal AR changed with development. In the cauda, AR level was highest on day 21 (0. 773±0. 028),intermediate on day 35(0. 762±0. 022),and lowest on day 90～120(0. 736±0. 008). The 90～120d group was significantly different from the 21d group (P＜0. 01)and 35d group (P＜0. 05). After the adult rats were treated with EDS to eradicate Leydig cells and endogenous testosterone, it was observed that the OPTDM of AR in the epididymal cauda epithelium was significantly reduced (P＜0. 001), and was restored to the control level by using ex- ogenous testosterone replacement (P＜0. 001). Conclusion These results suggest that the epididymal corpus depends least on androgens and the AR expression in the epididymis decreases with age and is dependent on circulating andro- gens.

Objective:To explore the correlation between the self-directed learning ability of medical students and the effect of flipped classroom teaching.Methods:The questionnaire survey was used. From November to December 2020, 123 students of 5-year program enrolled in 2019 in Peking University Health Science Center were chosen as the study objects and Neurobiology is a required course for them. The Medical Students' Autonomous Learning Ability Assessment Scale (MSALAAS) was used to assess the students' self-directed learning ability. The final examination score and a questionnaire survey were used to assess the teaching effect of the course. Descriptive analysis and Mann-Whitney analysis were used to analyze the change of self-directed learning ability of students after the course. One-dimensional linear regression was used to analyze the influence of self-directed learning ability on the final examination score, course experience and course assessment. Results:The total score of MSALAAS was increased from [(109.84 ± 14.12) points] to [(113.65±15.88) points] ( P<0.05) after the course. If the total score of the MSALAAS was referred to as an independent variant, and the final examination score, the course experience and course assessment was referred to as a dependent variable, respectively. The one-dimensional linear regression analysis showed that the total score of the MSALAAS was correlated with the final examination score ( B=0.248, t=3.59, P<0.001), the course experience ( B=0.049, t=3.15, P=0.002) and course assessment ( B=0.048, t=3.18, P=0.002). Conclusion:Flipped classroom teaching can promote the improvement of the self-directed learning ability of medical students. In converse, the students with higher self-directed learning ability might achieve higher examination score and get the better course experience and assessment.